1. Field of the Invention
The invention relates to selecting the best master enroll image used for identifying individuals from facial images, and more particularly from images of the eye. The master image may be used either in its original form or it may be used to compute a biometric code, such as an iris code which is stored and used for later comparisons.
2. Description of the Prior Art
There are several methods known as biometrics for recognizing or identifying an individual from personal biological characteristics. Some of these methods involve imaging of the face or eye and analyzing the facial features, retinal vascular patterns of the eye, or patterns in the iris of the eye. In recent years there has been a demand for more reliable systems to identify individuals, particularly those persons who desire access to a secured area or system. A common example of such a secured system is automated teller machines which allow authorized users to conduct banking transactions. Many of these systems are used by a wide variety of people. Very often these people demand quick as well as accurate identification.
A technique for accurately identifying individuals using iris recognition is described in U.S. Pat. No. 4,641,349 to Flom et al. and in U.S. Pat. No. 5,291,560 to Daugman. The systems described in these references require a clear and representative master enroll (template) image of the eye. The master enroll image is the image chosen to represent the unique characteristics of an individual, in this case, the characteristics of an individual's iris. The master enroll image is used as input to Daugman's algorithm to generate an iris code. The iris code extracted from the master enroll image is compared to a second iris code extracted from a current image of an individual whenever that individual's identity needs to be determined or verified. The present invention relates to selecting the best master enroll image to be used in such systems.